Control mechanism for changespeed gearing



1943- G. T. RANDOL 2,335,444

CONTROL MECHANISM FOR CHANGE SPEED GEARING Original Filed April 6, 19393 Sheets-Sheet 1 1777-0 EA/E/ Nov. 30, 1943. RANDOL 2,335,444

CONTROL MECHANISM FOR CHANGE SPEED GEARING Original Filed April 6, 19393 Sheets-Sheet 2 FIG 4 GLEN/V 7 FAA/00L) FTTO AA/EK Nov. 30, 1943. G. T.RANDOL 2,

CONTROL MECHANISM FOR CHANGE SPEED GEARING Original Filed April 6, 19395 Sheets-Sheet 5 Patented Nov. 30,1943

CONTROL lgFCHANISM FOR CHANGE- EEDG EARING Glenn 1 Randol, St. Louis,Mo., asslgnor to wuliam M. Liddon, Nashville, Tenn.

Original application April 6, 1939, Serial No.

266,348. Divided and this application September 10, 1941, Serial No.410,248

6 Claims. (Cl. 74-473) My invention relates to change speed gearing andmore particularly to mechanism for selecting and shifting the elementscontrolling the different speed ratios thereof.

This is a divisional application of my copending application Serial No.266,348, filed April 6, 1939, for Control mechanism for change speedgearing, which matured into Patent No. 2,258,068 dated October 7, 1941,and is directed to the selecting and shifting mechanism associated withthe shift* ing forks and mounted within the gearing housing.-

One of the objects of my invention is to provide improved means forselectively connecting the shifting forks of achange speed gearing tothe mechanism for performing the shifting of said forks wherebyunrestricted selection of the forks may be accomplished.

Another object of my invention is to provide means in a gear shiftingmechanism whereby the member for performing the shifting will have auniform distance of travel to accomplish the shifting of each of theelements of the gearing, notwithstanding said elements must be moveddifferent distances to be placed in an operative position.

Other objects of my invention will become apparent from the followingdescription taken in connection with the accompanying drawings in whichFigure 1 is a side view of a portion of a motor vehicle power plantshowing a change speed gearing provided with a shifting mechanismtherefor embodying my invention; Figure 2 is a perspective view of thehand selecting mechanism mounted on the steering column of the vehicle;Figure 3 is a cross-sectionalview taken on the line 3-4 of Figure 2;Figure 4 is a view of the mechanism within the gearing housing with thecover removed and showing the parts thereof in their respectivepositions when the gearing is in neutral; Figure 5 is a view similar toFigure 4 but showing the parts in the positions they assume when thegearing is in high'speed ratio: Figure 6 is a partialcross-sectionalview of the control valve and related parts showing their po- 'sitionswhen the'gearing is in neutral; Figure 7' is a view similar-to Figure 6but showing the control valve and related parts'in'the positions theyassume when the gearing is in high speed ratio condition; Figure 8 is aperspective view of the the lever connection between high and secondspeed shifting forks and the carrying rail; Figure 12 is a view, partsbeing shown in section, of a portion of the change speed gearing showingit in high gear position; Figure 13 is a perspective view of therotatable selector control member for controlling the connecting pawlson the shifting yokes; and Figure 14 is a view similar to Figure 7 butshowing the valve and related parts in the positions they assume whenthe valve is shut off and the clutch pedal is in clutch-engagedposition.

Referring to the drawings in detail, and particularly to Figure 1,numeral I indicates the internal combustion engine of a motor vehiclewhich is connected by means of the usual clutch 2 to the change speedgearing 3 whereby the driven shaft 9 of the gearing may be rotated atdifferent speed ratios to drive the wheels of the vehicle through thepropeller shaft (not shown). The clutch 2 is of conventionalconstruction and the disengageable elements thereof are controlled by ashaft 5 extending to the exterior of the clutch housing and having aclutch pedal 6 secured thereto to be actuated by a foot of the operatorof the vehicle. The change speed gearing 3 with which my improvedcontrol mechanism is associated is also of conventional design and isenclosed within the gearing housing 1 secured to the clutch housing bybolts 4. Since this gearing forms no part of my invention, it is notdisclosed in detail. However, in Figure 12 I. have disclosed a portionof this gearing in order to better show,

- cooperate with a slidable clutch element l3 splined to a member I4secured to the driven shaft 9. The driven shaft 9 also has rotatablymounted thereon a gear 15, this gearing being constantly driven by agear IS on the countershaft .(not shown). The gear I5 is provided withclutch teeth I 6 which'also cooperate with theslidable clutch element I3. Thus when the'clutch element is in the position shown in Figure 12,shaft 8 will be directly'connected to shaft 9 and high or direct speedratio will be operative. If the clutch element is moved to the right sothat it engages the clutch teeth It, gear l5 will be connected to thedriven shaft 9 and second speed ratio will be operative. The drivenshaft 9 has slidably splined thereon a gear H which is slidable in theforward direction to engage with a gear l8 driven by the counter-shaftfor securing low speed ratioand'slidable rearwardly to engage with anidler gear l9 driven by means of a gear l9 on the counter-shaft to thussecure reverse speed ratio.

In accordance with my invention I detachably mount upon the housing 1, asupporting housing 28 and a cover 2|. The supporting housing 28 hasslidably mounted thereon parallel rods 22 and 23 and secured to rod 22is a shifting fork 24 which controls the gear H for the low and reversespeed ratios of the change speed gearing. The rod 23 has loosely mountedthereon a shifting fork 25 which cooperates with the sliding clutchelement |3 (Figure 12) for shifting this clutch element to cause thehighand second speed ratios to be operative and inoperative as desired.

shifting fork 24 for the same movement of either rod 23 or 22, I providean arm 28 which is pivotally connected at 21 to the supporting housing28 and also with shifting fork 25 and rod 23. The connection between thearm and the shifting fork is at a point closer to pivot 21 than theconnection between the arm and rod 23. Therefore, as the rod is moved ineither direction from a central position, as shown in Figure 5, the armwill cause shifting fork 25 to move a distance less than the distancewhich rod 23 will move.

Rods 22 and 23 have mounted thereon companion connecting devices 28 and29 for connecting the rods to a single member to perform the shifting ofthe forks. The device 28 and the rods are shown in'detail in Figure 10.Each of these devices 28 and 29 comprises two spaced plates 38 and 3|having openings therein for receiving rods 22 and 23 and these plateshave welded thereto a tubular member 32 which lies between the rods. Theplates 38 and 3| have pivotally mounted therebetween two detents 33 and34 which are spring-biased toward the rods by means of a single leafspring 35. The rod 22 has cut therein on its underside spaced slots 38and 31 and rod 23 has similar slots 38 and 39. The detent 34 in theconnecting device 28 is adapted to cooperate with slot 38 in rod 23 anddetent 33 of this same device cooperates with slot 38 in rod 22. Thedetent 34 of the connecting device 29 cooperates with slot 31 in rod 22and detent 33 of this device cooperates with slot 39 in rod 23.

The two tubular portions 32 of the companion connecting devices arealigned and receive a rotatable selector control member 48 journaled on-stub-shafts 4| and 42 in the ends of the supporting member 28. Theouter surface of this selector member is provided with elongatedrecesses 43, 44v 45 and 48, the former two being in one end of themember and in circumferentially spaced relation and the latter two beingin the other end of the member and also in circumferentially spacedrelation. The recesses 43 and 44 cooperate with detents 33 and 34,respectively, on the device 28 and recesses 45 and 48 cooperate withdetents 33 and 34, respectively, on device 29. The detents 33 and 34 areprovided with projecting portions 41 and 48 which extend through slotsin the tubular member 32 whereby the detents may be properly controlledby the recesses in the selector control member 48.

The control '.member' 48 has'operatively connected thereto a bevel gear49 which meshes with a gear 58 carried by a shaft 5| mounted in cover2|. The outer end of this shaft has secured thereto a lever 52, and arod 53 connects this lever to a lever 54 on theend of a shaft 55rotatably mounted in the brackets 58 and 51 on the steeringcolumn 58.The upper end of shaft 55 'has' secured thereto a tubular arm 59 andslidable therein is a hand. lever 88. This lever carries a pin 8| whichprojects upwardly into an H-slot 82 in the top of the bracket 51 whichis positioned just below the steering wheel 83. The surface of thebracket carries suitable indicia R, "1, 2, and 3 in order to designatethe different legs of the H-slot whereby. the operator will haveknowledge of which speed ratio is selected when pin 8| is placed in theend of a particular slot. The lever 88 is normally biased by a spring 84to a position where pin 5| is in a slight recess in the end ofthecross-over slot and in alignment with the slots designated "2 and 3".

From the previously described structure it is apparent that the shiftingforks 24. and 25 maybe selectively connected to either of the companionconnecting devices 28 and 29 as desired. Thus,

if the hand lever 88 is pushed inwardly and pulled downwardly so thatpin 8| assumes a position at the end of the slot marked 1", therotatable control member 48 will be rotated to such a position that theprojecting portion 41 on detent 33 of device 28 will be biased into theelongated recess 43, thereby permitting the detent to engage in slot 38in rod 22, and connect the shifting fork 24 to device 28.

If lever 88 is moved out of the end of the slot "1 and into the end ofslot "2, this will cause the rotatable control member 48 to assume aposition where the projection 41 on detent 33 of device 29 will bebiased into the elongated recess 45, thereby permitting the detent 33 toengage in slot 39 on rod 23, thus connecting the device 29 with rod 23.

If lever 88 should be moved downwardly so that pin 8| is in the end ofthe slot marked "3, the rotatable control member 48 will assumeaposition where projection 48 on detent 34 Of device 28 will be biasedinto the elongated recess 44, thereby permitting detent 34 to engage inslot 38 to connect device 28 to the rod 23.

If lever 88 should be moved so that pih 8| is at the end of the slotmarked R, the rotatable control member 48 will be moved to a positionwhere projection 48 on detent 34 of device 29 will be biased intoelongated recess 48 and thereby permit detent 34 to engage in slot 31 ofrod 22 to connect device 29 to saidrod.

In order to prevent the movement of rods 22 and 23 when one is'moved tooperative position, there is provided the usual interlock device 2.Detent devices 3 maintain the rods in their different positions.

In order that the devices 28 and 29 may be moved in opposite directionsfrom and to their neutral positions, as shown in Figure 4, to move theshifting forks and the gearing elements connected thereto to operativeand inoperative positions, respectively, plate 38 of the device 28 isprovided with a projecting portion 85 overlying the gearing shiftingfork 25, and plate 38 of deaasmu vice 28 is provided with a projectingportion 88 overlying the shifting fork 24. Journaled in cover 2| is ashaft 81 which extends toa point between projections 85 and 88 and uponthe end of this shaft is secured a double arm lever 88, one arm of whichis pivotally connected to projection 85 and the other arm to projection88. It is thus seen that if shaft 81 is rotated in a clockwise directionfrom the position shown in Figure 4, devices 28 and 28 will be movedoutwardly to the positions shown in Figure 5 and return rotation of theshaft will cause the devices to be returned to their neutral orinoperative positions.

The outer end of shaft 51 hassecured thereto a lever 88 formed of twospaced members 18 and 1| riveted together. The lower arm of this lever"is pivotally connected to a piston rod 12 operated by a piston 13reciprocable in a cylinder 14 secured to the side of the gearinghousing, said piston and cylinder forming a suction motor or powercylinder for rotating shaft 81.

In order that the suction motor may be properly controlled, I provide avalve 15 mounted upon cover 2 I, this valve comprising a cylindricalvalve casing 18 and a valve element 11 slidable in the casing. One sideof the casing is provided with a port 18 which is connected by means ofa conduit 18 to the intake manifold 88 of the internal combustionengine, this intake manifold serving as the source of suction foroperating the suction motor. The opposite side of the valve casing 16 isprovided with spaced ports 8| and 82, the former being connected by aconduit 83 to the rear end of the suction motor cylinder 14 and thelatter connected by a conduit 84 to the forward end of said cylinder.

The slidable valve element is provided with an elongated recess 85 inconstant communication withport 18 and communicating with this recessare grooves 88 and 81 for cooperation with ports 8| and 82,respectively. The valve element is also provided with a central bore 88and a passage 88 for connecting the port 82 to atmosphere by means ofthe opening 88 in the ends of the valve casing. A passage 8| is providedfor connecting port 8| to atmosphere. The valve element is normallybiased by means of a sprin 82 to a position where ports 8| and 82 are incommunication with atmosphere as shown in Figure 14.

The valve element 11 is operated by means of a stem 83 which extendsinto cover 2| and is provided with a roller 84 for cooperation with acam 85 rotatably mounted upon shaft 81. The surface of this cam isprovided with a, recess 88, lands 81 and 81' of uniform height on eachside of the recess and another land 88 of greater height. When theroller is in recess 86. the valve will be in the position shown inFigure 14 wherein both ends of the cylinder of the suction m tor are incommunication with atmosphere. When the cam is in the position whereroller 84 cooperates with either land 81 or 81', the valve will be inthe position shown in Figure 7, thereby placing the forward end of thecylinder of the suction motor in communication with the manifold and therear end in communication with atmosphere. When the cam is in theposition where roller 84 cooperates with land 88, the valve will be inthe position shown in Figure 6 wherein t e rear end of the cylinder ofthe suction motor will be in communication with the manifold and theforward end in communication with atmosphere.

The hub portion of cam 85 is interlocked with the hub portion of an arm88 also rotatably g 3 mounted upon shaft 01. The outer end of this armis connected to a spring I88 attached to cover plate 2|, thu normallybiasing the arm to a horizontal position and placing thecam in apositionwhere roller 84 cooperates with recess 88 and the valve elementconnects both ends of the cylinder of the suction motor to atmosphere.The body of arm 88 is formed, with a slot I8I for receivinga pin I82carried on the rear end of a link I83 positioned between the spacedmembers .18 and H of lever 88. The forward end of link I83 is connectedto an arm I84 fixed to the clutch actuating shaft 5. 'The membersforming lever 88 are so shaped as to provide converging cam surfaces I85and I88 adjacent the pivotal axis of the lever, said surfaces extendingrearwardly and meeting to form an apex I81. This apex is adapted to lieupon either one side or the other side of a horizontal line passingthrough the axis of the shaft, thus placing either the'surface I85 orI86 for engagement with pin |82 depending upon the position of lever 58.Pin I82, prior to engagement with either surface I85 or I88, is

' guided in a horizontal line by slot III in arm 88.

' operating gears.

Each upper arm of the members forming lever 88 is provided with a notchI88 at the base of the cam surface I and each of the lower arms isprovided with a notch I88 at the base of cam surface I88. The camsurfaces I85 and I88 cooperate with pin I82 to cause the pin to so moveas to rotate cam 85 for controlling the valve and to also guide the pininto the notches I88 and I88 depending upon the position of apex I81, In

' order that the clutch pedal 8 and lever I 84 may shown in Figure 5.The shifting forks will be in a position wherein the clutch element I3is disengaged and gear I1 is out of mesh with its co- If the clutchpedal is in engaged position as indicatedby the dashed lines (Figure l),the piston of the suction motor will be in the forward end of thecylinder and the lever 68 will be in the position shown in Figure '7.The control cam 85 for the valve 15 will be in the position shown inFigure 14 with the control arm 88 being held in a rearward horizontalposition by spring I88 as shown in the same figure. Both ends of thecylinder of the suction motor will be in communication with atmosphere.

If it is now desired to place the change speed gearing in its first orlow speed position, hand lever 88 is so moved as to place pin 8| 'in theend of the slot marked 1.- As already described, this will result in therotation of the rotatable control member 48 to a position where theprojecting portion 41 on detent 33 of the connecting device 28 will bepermitted to engage in the elongated recess 43. If the clutch pedal 8 isnow moved forwardly, the initial movement thereof will cause the clutchto become disengaged. The pin I82 on the end of link I83 during thismovement of the pedal will ride forwardly in slot I8I of the valve camcontrol arm 88 and no part of of the clutch pedal will cause pin I82 toengage tion of apex III! on lever 89 which is as shown inFigure 14, 'Thepin I92 will now move along this cam surface, thereby rotating arm 99and also the cam in a counter-clockwise direction. Rotation of the cam'will cause land 91 to move beneath the roller 94 and place the valveelement 11 in the position shown in Figure 7. The front end of thesuction motor will now be connected to the manifold and the'rear end ofthe suction motor will remain in communication with atmosphere. Thepiston of the suction motor will not be moved since the differentialpressures acting thereon are tending to move it forwardly and it isalready in its normal or, forward end of the cylinder.

Continued forward movement of the clutch pedal will rotate the camthrough an additional angle so the cam will assume the position whereland 98 will engage roller 94 of the valve stem and force the valveelement 1'! to the position shown in Figure 6. This will cause the rearend of the suction motor to be placed in communication with the manifoldand the forward end of the suction motor to be placed in communicationwith the atmosphere. The differential pressures now acting upon thepiston of the suction motor will cause the piston to be moved to therear end of the cylinder, thereby swinging lever 89 in acounter-clockwise direction to the position shown in Figures 1 and 6.The shaft 81 and lever 88 thereon will be moved to the position shown inFigure 4, thereby causing the connecting devices 28 and 29 to be movedto their innermost positions. When the devices have reached thesepositions, detent 33 of the connecting device 28 will engage in slot 38in rod 22 under the action of spring 35, thereby connecting rod 22 tothe connecting device 28.

When the cam assumes a position where roller 94 begins to cooperate withland 98, pin I92 will where roller 94 will again engage recess 99 of thecam and permit the valve to assume the position where both ends of thesuction moto are 1 theless, return to the position shown in Figure 14.Since lever 89 continues to remain in the position shown in Figure 6,apex I91 of the two converging cam surfaces on lever 89 will lie abovethe horizontal line assumed by arm 99.

begin to engage in notch I98 and link I93 can apply some manual force tolever 89 to assist, if necessary, in moving the lever from the positionshown in Figure 7 to the position shown in Figure 6. If the suctionmotor should completely fail to operate lever 89, this lever,nevertheless, can be rotated by manual force in the counter-clockwisedirection to bring the connecting devices 28 and 29 to their innermostpositions.

When theclutch pedal 8 is released, arm 99 and cam 95 for the valve willbe rotated in a clockwise direction by the return movement of link I93and the pulling action of spring I99. When land 91 again cooperates withroller 94, valve element 'Il will assume the position shown in Figure7., This will connect the forward end of the suction motor with themanifold and the rear end of the suction motor with the atmosphere. Thedifferential pressures now acting upon the piston will cause the pistonto move to the forward end of the cylinder, thereby swinging lever 89from the position shown in Figures 1 and 6 to the position shown inFigure 7. This will now cause the connecting devices 28 and 29 to bemoved to their outermost positions as shown in Figure 5. Since rod 22 isconnected to the connecting. device 28, thi rodand the shifting fork Iwill be carried therewith and cause gear II to engage gear I8 of thegearing and place the gearing in low speed. As the clutch pedalcontinues its return movement, the clutch will be engaged and the valvecam arm 99 and the cam return to the positions shown in Figure 14 If newthe clutch pedal should be'again depressed. which is a natural movementfor the operator when he realizes that the desired gear ha not becomeengaged, pin I92 will be moved forwardly and engage cam surface I88.This cam surface will cause the pin to be Buided into notch I99 andprovide a direct mechanical connection between link I93 and the lowerarm of the lever. Continued forward movement of the clutch pedal willnow cause manual force to be applied to lever 89 and thus rotate thelever in a clockwise direction to cause it to assume the position shownin Figure 7 wherein gear I! will b moved to operative position in amanner already described.

It is also to be noted that as the clutch pedal is again moved forwardlywhen the operator becomes conscious that th selected gear has not beenmade operative, pin I92 will also cause arm 99 for the valve cam to berotated in a clockwise direction. This will result in land 81' tocooperate with roller 94 and move the valve to the position shown inFigure '7. The forward end of the suction motor will thus be placed incommunication with the manifold and the rear of the suction motor willbe placed in communication with atmosphere. Thus, if there is anydifferential force acting upon the piston of the suction motor, it willbe effective in assisting the manual force being applied by the operatorto rotate the lever 89 in a clockwise direction to cause it to assumethe position shown in Figure 'I.

If it is now desired to place the change speed gearing in second speedposition, the hand lever beneath the steering wheel is moved to aposition where pin 8| is in the'end of the slot marked 2. The rotatablemember 49 will now be moved to a position where the elongated recess 45will cooperate with the projection 41 on detent 33 of the connectingdevice 29. This rotation of the rotatable control member will also causedetent 33 of the connecting device 28 to be disengaged from slot 38 onrod 22. If new the clutch pedal is again disengaged, the connectingdevices 28 and 29 will be brought to their central positions as shown inFigure 4 by ,the operation of the suction motor in a manner alreadydescribed, thereby disengaging gear II. If said suction motor fails,manual force may be applied to the lever through link I93 and pin I92,the latter engaging in notch I98 of lever 89. The inward movement ofconnecting devices 28 and 29 will cause the shifting fork 24 to be movedagain to ready described to rotate lever 83 to the position shown inFigure 7, thereby causing the connecting devices 28 and 29 to be movedto their outer positions, the connecting device 29 carrying with it rod23 and shifting fork 25. This will cause the clutch element II toconnect gear I! to driven shaft 8, thereby causing second speed ratio tobe operative. If during the return movement of the clutch pedal thesuction motor should fail to perform the shifting of devices 28 and 29apart, a subsequent downward movement of the clutch will result in theshift being made by manual force or by a manual force and a forcederived from the suction motor in the manner alreadv described.

If the transmission is desiredto be placed in high speed position, handlever 60 is moved so pin 8| is in the end of the slot marked 3. Therotation of the rotatable control member 48 will now cause detent 33 tobe disengaged from slot 39 in rod 23 and the elongated recess 44 placedin a position to receive projection 48 on detent 34 of connecting device28. Downward movement of the clutch pedal will now cause the connectingdevices 28 and 29 to be moved to their inner positions, plate 39 of theconnecting device 29 carrying with it the shifting fork 25 tothusdisengage the clutch element l3 from the clutch teeth of the secondspeed gear Ii. When the connecting devices 28 and 29 reach theirinnermost positions, as shown in Figure 4, detent 34 of device 29 willengage in slot 38 of rod 23, thus connecting the rod to said connectingdevice. When the clutch pedal is released, the connecting devices 28 and29 will be moved to their outermost positions, device 28 carrying withit rod 23 and thereby moving shifting fork 25 to a position where theclutch element l3 will directly connect shaft 8 of the gearing to drivenshaft 9, thus causing high speed to be operative.

When reverse speed is desired, hand lever 80 is placed in a positionwhere pin 8| is in the end of the slot marked R." This willplace therotatable control member 48 in a position where projection 48 on detent34 of connecting device 29'will be able to cooperate with the elongatedrecess 48. The other detents will be moved to inoperative positions.Downward movement of the clutch pedal will result in the connectingdevices 28 and 29 being moved to their inner positions where detent 34of connecting device 29 will engage in slot 31 of rod 22. Returnmovement of the clutch pedal will cause the connecting devices 28 and 29to be moved to their outer positions and the shifting fork 24 carriedwith the connecting device 29 to a position where gear I! will be inmesh with the idler gear I9 to cause reverse speed to be operative.

From the foregoing description it is apparent that I have produced avery simple and eiiicient control mechanism for a change speed gearingwhereby any gear ratio can be selected by a movement of the hand leverand this gear ratio caused to be operative by movement of the clutchpedal which conforms with the clutch engaging and disengaging movements'of said .pedal. Any gear ratio of the change speed gearing may beselected at any time regardless of whether the gearing is in neutral orin a gear ratio operative position. The shifting of the gears isnormally performed by power, thus not placing any additional strain uponthe leg of the operator. However, the construction is such that in theevent the shifting of the gear or clutch is not accomplished by thesuction motor, the shift may, nevertheless, be made by manual force ormanual force may be empioyed to assist thesuction motor to make theshift. The gearing is always neutralized on the down stroke of theclutch pedal, notwithstanding 5 the failure of the power means forperforming the shifting operation since the clutch pedal will bedirectly connected to the gear shifting mechanism clutch-engagedposition, then a subsequent downward stroke of the clutch pedal willresult in the shift being made by manual force. This is a very importantfeature of my invention since the method of operation follows theoperators natural actions when the shift is not made by means of thesuction motor. The natural thing to do when something fails is to try todo it over again. Thus, when the operator becomes conscious of the factthat the return movement of the clutch pedal has failed to cause theselected gear ratio to become operative, his first action is to push theclutch pedal down again and then allow it to return. This subsequentdownward movement of the clutch pedal is employed to permit the operatorto apply manual force to the member bein 0 shifted. The control of thevalve is such that it will always tend to cause the suction motor toassist the manual force employed to shift the gearing elements. Thus;the operator will never be called upon to do all the gear shifting bymanual force unless the suction motor is totally inoperative.

.My novel control mechanismis also readily attached to the presentlyused change speed gearing either as an accessory or as standardequipment. When so applied, the same gear shifting forks and rods may beemployed. it only being necessary to cut the required notches in therods.

Being aware of the possibility of modifications in the particularstructure herein described without departing from the fundamentalprinciples of my invention, I-do not intend that its scope be limitedexcept as set forth by the appended claims.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In control mechanism for a change speed gearing having a shiftingfork for controlling difierent speeds thereof, a rod for moving thefork, two devices mounted for longitudinal sliding movement in oppositedirections, each of said devices comprising two spaced plates throughwhich the'rod extends, a pivotally mounted detent positioned between theplates of each device,

a spring for biasing each detent toward an operative position, meansforming notches in the rod for receiving the detents, a rotatablecontrol member fixed against axial movement, means on said controlmember and the detents for selectively permitting the detents to engagethe notches, and means for simultaneously moving the devices in oppositedirections.

2. In control mechanism for a change speed gearing having a shiftableelement for controlling different speeds thereof, two members mountedfor longitudinal sliding movement in tatable member for selectivelycausing said detachable connecting means to be conditioned for rections,means comprising spring-biased detents carried by the members forconnecting them to the rod, means comprising a rotatable memberpositioned adiacentthe members and provided with means thereon directlyengaging with parts of the detents for selectively causing the detentsto be conditioned for operation or to be inoperable in any position ofthe members, and means for moving said members in opposite directions.

4. In control mechanism for a change speed gearing having two shiftableelements for controlling diflerent speeds thereof, two members mountedon the shiftable elements in axially spaced relation for longitudinalsliding movement, means comprising two detents pivotally mounted on eachmember for connecting said members to either of said shiftable elements,a rotatable member fixed against longitudinal movement with its axisextending in the direction of sliding movement of the members and beingprovided with elongated recesses for selectively receiving parts of thedetents and causing said detents to be conditioned for operation in anyposition of the members, and means for simullongitudinal slidingmovement in opposite di- I taneously moving said members in oppositedirections.

5. In control mechanism for a change speed gearing having two parallelshiftable rods, shifting forks on the rods for controlling the differentspeeds thereof, two members mounted on the rods for longitudinal slidingmovement only, means comprising detents pivoted on said members andcooperating notches in the rods for selectively connecting said membersto either of said rods, means comprising a rotatable member positionedbetween and parallel with the rods and provided with longitudinalrecesses and ridges cooperating with the detents for controlling saiddetents, said members when moved longitudinally having relative movementwith respect to the rotatable member, and means for simultaneouslymoving said members in opposite directions.

6. In controlmechanism for a change speed gearing having a shifting forkfor controlling different speeds thereof, a rod for moving the fork, twomembers mounted in Juxta-position to.

the rod for longitudinal sliding movement in opposite directions, meanscomprising detents pivotally carried by the members for connectingeither member to said rod, a rotatable selector rod positioned parallelto said rod and fixed against axial movement, means on therotatableselector rod directly cooperating with the detents forselectiveb' controlling the conditioning of A

